fix #1031

[dogdie233]

What cause the issue

In line 94

YamlDotNet/YamlDotNet.Analyzers.StaticGenerator/TypeFactoryGenerator.cs

Lines 92 to 98 in b8ac2a9

	var namespaceName = syntaxReceiver.YamlStaticContextType?.ContainingNamespace.ContainingNamespace;
	write($"namespace {syntaxReceiver.YamlStaticContextType?.GetNamespace() ?? "YamlDotNet.Static"}", true);
	write("{", true); indent();
	new StaticContextFile(write, indent, unindent, _context).Write(syntaxReceiver);
	new StaticObjectFactoryFile(write, indent, unindent, _context).Write(syntaxReceiver);

When the StaticContext to be generated is in the global namespace, syntaxReceiver.YamlStaticContextType?.GetNamespace() returns an empty string instead of null. As a result, the ?? operator does not take effect.

So, the generated code in YamlDotNetAutoGraph.g.cs ends up as follows:

...
namespace 
{
    ...

Since there is no identifier following namespace, the compilation fails.

About unit test case

Due to the stringent conditions required to trigger this issue, I am unsure how to write a unit test. Should I create a new console project to reproduce the issue?

A potential problem

When the auto-generated StaticContext is in the global namespace, other classes, such as StaticObjectFactory, will also be created in the global namespace. This could potentially conflict with other classes.